Alpha 2-macroglobulin is a glycoprotein containing 8-11% carbohydrate which can be isolated from plasma by gel filtration chromatography.
Alpha 1-proteinase inhibitor (alpha 1-antitrypsin) is a glycoprotein having a molecular weight of 53,000 determined by sedimentation equilibrium centrifugation. The glycoprotein consists of a single polypeptide chain to which several oligosaccharide units are covalently bonded. Human alpha-1 proteinase inhibitor has a role in controlling tissue destruction by endogenous serine proteinases. A genetic deficiency of alpha-1 proteinase inhibitor, which accounts for 90% of the trypsin inhibitory capacity in blood plasma, has been shown to be associated with the premature development of pulmonary emphysema. The degradation of elastin associated with emphysema probably results from a local imbalance of elastolytic enzymes and the naturally occurring tissue and plasma proteinase inhibitors. Alpha-1 proteinase inhibitor inhibits human pancreatic and leukocyte elastases. See Pannell et al, Biochemistry. 13, 5339 (1974); Johnson et al, Biochem, Biophys. Res. Commun., 72 33 (1976); Del Mar et al, Biochem. Biophys. Res. Commun., and Heimburger et al, Proc. Int. Res. Conf. Proteinase Inhibitors. 1st, 1-21 (1970).